What is the Laver Cup, why are Roger Federer and Rafael Nadal playing and how excited should we be about it?
What is it?
The Laver Cup, which was announced in August 2016, is tennis's answer to golf's Ryder Cup and pits Team Europe against Team World. It is one of a number of new tennis events that has sprung up in the last few years to shake up the conventional tennis calendar, such as the Next Gen ATP Finals and Tie Break Tens.
When is it?
The inaugural Laver Cup will take place on Friday September 22 to Sunday September 24.
Where is it?
The O2 arena in Prague, on an indoor hard court.
How can I watch it?
Sky Sports will be showing the event.
How will it work?
The competition (named after Australian tennis legend Rod Laver) will see a team of the six best players from Europe against six of their counterparts from the rest of the world. Four of each team's players are chosen based on the world rankings, and then both team captains are allowed two wild card picks.
The Laver Cup will be held across five sessions over three days. On Friday and Saturday the day session features two singles matches and the night session features a singles and a doubles match
The deciding session on Sunday will feature from one to five live matches – as many as necessary to determine the winner.
Matches will be the best of three sets, with the final set a 'champions tie-break' of first to 10 points. If the teams are tied at the end of the first 12 matches then a final best of one set doubles match will be played.
On Thursday, the team captains will submit their lineup cards for Friday’s matches to the referee in a blind exchange, with match-ups revealed at an on-court ceremony.
For days two and three, one captain will submit his card blind in the morning for the opposing captain to review before selecting his players.
As the hosts, the Team Europe captain will choose which day he wants the home advantage and submit his playing lineup after reviewing Team World’s selection
Each match on Friday is worth one point, two points per match are up for grabs on Saturday, and three points for each match on the crucial deciding Sunday
The first team to reach 13 points will win the inaugural Laver Cup, with the doubles decider played if the scores are level at 12-all on the final day.
Each player must play at least one singles match, and a minimum of four of the six players must play doubles. All players will sit on court watching their team-mates' matches.
Who is involved?
Team Europe will be captained by Bjorn Borg, while Team World will be captained by his one-team adversary John McEnroe.
The team line-ups are as follows:
Team Europe
Roger Federer (Switzerland)
Rafael Nadal (Spain)
Marin Cilic (Croatia)
Dominic Thiem (Austria)
Alexander Zverev (Germany)
Tomas Berdych (Czech Republic)
Federer and Nadal's presence means there is the tantalising prospect of arguably the two greatest players of all time teaming up for the doubles.
Team World
Jack Sock
Sam Querrey
John Isner (all USA)
Nick Kyrgios (Australia)
Frances Tiafoe (Australia) - a late replacement for Juan Martin del Potro (Argentina)
Denis Shapovalov (Canada)
Will there be ranking points at stake?
No, there is just pride and shedloads of money at stake. Which leads me to...
How much will the players be paid?
It is not known exactly, but the appearance fees being offered to the players - Federer and Nadal especially - is believed to be 'substantial'.
How often will it be played?
Every year for at least the next three years, with Borg and McEnroe signed up for that period. The location will rotate between major cities in Europe and the rest of the world each year, and will be staged two weeks after the US Open, except in summer Olympic years.
Does tennis really need another competition?
Probably not, especially given the high injury count this year and the massively over-crowded calendar. The Davis Cup will be especially peeved, given its difficulties attracting the top players as it is, and the fact that its semi-finals were last weekend so there was an obvious clash.
But with Federer and Nadal on board, it's possible that this could be the all-star international team tournament that tennis has been lacking in the last 20 years or so. In the 1970s, the Davis Cup was considered almost as prestigious as the grand slams, but its importance has waned over time. The fact that there have only ever been two matches between 'Big Four' members in the Davis Cup - and none since 2009 - underlines its struggles to be taken seriously.
What are they saying?
Federer: "After all these years I actually get a chance to support his forehand, his aggressive play, his fighting spirit, his everything. He's been a wonderful champion for our sport.
"I think Rafa brought something to the game that we really haven't seen that much before, or not at all. The amount of spin he was able to bring to the game or the physicality and his movement on clay."
Borg: "Doubles is going to be very important. I think everybody wants to see, of course, Federer and Nadal play doubles,” he said.
"It’s very important to choose who is going to play (and) how many matches when they’re going to play."
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McEnroe: "If I start yelling and screaming, and that makes the player that’s playing play worse then that’s a bad idea."
"Obviously it’s mainly up to the player but hopefully as a coach (if I) can help maybe a little bit at the right moment then you feel like you did your job."
Who will win?
Europe are the massive favourites - their team boasts 36 grand slam titles to their opponents' one.
